Over - depreciated assets

SUGGESTED

Hi - I have two questions.  First, back in 10/31/19, we changed the estimated lives of all assets that had either 30 years or 27.5 years to 40 years in the tax books.  At that time, we made the change using the "current thru date" not realizing that the new depreciation would cause our assets to be over depreciated.  We now know that if we had used the "RV" method the assets would be depreciated over the remainder of the new life.  Is there a way to correct the over depreciation now?  We also have to make this adjustment in bulk because of the volume of assets that have to be changed.  If we are able to fix the depreciation using the RV method, will the acquired value that we see on the reports change? 

My question is relating that the change, we had an accounting firm make the changes to our lives outside of the system in order to file the 2018 tax returns.  Can we change the 1/1/2019 prior accumulated deprecation to match what the accounting firm determined should be the accumulated depreciation?  Not sure if it is possible to force this number?